Improvement in manufacture of white lead



B. F. SMITH.

Manufacture of White Lead.

Patented Nov. 9, [858.

UNITED STATES PATENT OFFICE.

IENJAHIN F. SMITH, OF NE\V YORK, N. Y.

IMPROVEMENT IN MANUFACTURE OF WHITE LEAD.

Specification forming part of Letters Patent No. 22,036, dated November9, 1858.

To all whom it may concern.-

Be it known that I, BENJAMIN F. SMITH, of the city of New York, in thecounty and State of New York, have invented a certain new and usefulImprovement in the Manufacture of White Lead; and I hereby declare thefollowing to be a full, clear, and exact description of the same,reference being had to the accompanying drawings, which form part ofthis specification, and in whieh- Figure 1 represents a front elevationof an apparatus for carrying into effect my new process in themanufacture of white lead; Fig. 2,-a side view thereof, and Fig. 3 avertical transverse section of the same.

W'hite lead is produced by converting metallic lead. into carbonate ofoxide of lead by either precipitating it from a solution of a salt oflead by means of carbonic acid or by carbonating the metallic lead undercircumstances which effect the combination of the generated oxide oflead with carbonic acid. The latter mode has the advantage over theformer, inasmuch as the product has more body or is of a more earthy ordense consistency, answers the purpose of paint better,

and is called b T chemists amorhus white lead, in contradistinction tothe production by the first process, which is of semi-crystallineformation. The general principle upon which the latter method isconducted consists in exposing metallic lead to suitable acid fumes andafterward or simultaneously to carbonic acid, to which method ofmanufacture my invention relates. In such treatment of metallic lead itnecessarily follows that the more extended the surface for a givenquantity of the metal and the greater the exposure of its particles andfreedom of circulation in, on, and around it the more thorough,economical, and rapid is its conversion into white lead produced by thecombined action of the acetic vapors and carbonic acid. Much attention,therefore, has been bestowedon preparing the metallic lead for suchexposure. The present most advantageous method appears to be to pourmelted lead on aniron plate placed over a boiler and on the surface ofthe metal beginning to consolidate, sloping the plate so as to run offthe still liquid metal and leave a lead sheet of extreme thinness.

A series of these sheets is then suitably hung in a close box for theaction of the acids, as specified.

My improvement has for its object the preparing in a better form for theaction of the acids the metallic lead, and at the same time to simplifyand expedite the process.

I do not confine myself to any particular form or arrangement ofdetails, as these may be almost infinitely varied, but in theaccompanying drawings and following description will be found explaineda means for carrying my new process into effect which is sufficient istapped or allowed to run off, as required by a horizontal or inclinedpipe 0, terminating in a cross perforated pipe or sprinkler D,theperforations in which are supposed to be arranged along the lowersurface of it and of suitable size and arrangement as to permit of themelted lead being discharged therefrom in thin and divided streams at asuitable distance apart. Underneath this sprinkler and parallel with itis shown a horizontal and corrugated cylinder E, arranged at any givendistance from the sprinkler, and which may be situated in a lowerchamber of the building,

so as to receive on its top in front the streams or shower of metalliclead in its fluid state issuing from the sprinkler. The corrugations inthe cylinder are here represented annularly around the cylinder andpitched to correspond with the perforations in the sprinkler. The leadforming or dividing the corruga tions may be of arched form in theircrosssection. This cylinder E is madehollow and mounted in suitablestandards at either end and is designed to rotate rapidly in thedirection indicated by the arrow min Fig. 2. It

keeping up a running supply of cold water to it internally or throughit.

From this description it will be seen that the stream of melted leadfalling from the sprinkler on the corrugated surface of therapidly-revolving cooling-cylinder will be almost instantaneouslysolidified. and broken and thrown off by the centrifugal force in aseries of thin detached spangles of rough formation and more or lessarched in accordance with the curvature of the cylinder. These spanglespresent, therefore, a most advantageous and extensive surface for thesubsequent action of. the acetic vapors on and through or among them bysuitably piling on racks in aclose chamber for the purpose, and are inevery way superior and more convenient than sheets or coils, asheretofore used, while the rapidity and economy with which they may beproduced form also considerations of some importance. It will be readilyperceived that substantially the same operation is effected by anymanner of cansing the stream of lead to pass through perforationsarranged longitudinally in relation to each other and parallel with theaxis of the rotating cylinder.

In Winteri. c., when the surrounding atmosphere is comparatively cold orwhenthe material of which thepot and its apptlrte' nances areconstructed are of such a thick ness as to cause the lead to coagulateand to clog up the orificesI surround the outletpipe with burningcharcoal placed in an augur provided with a series of orifices at itslower edge, and which I use instead of the perforated pipe. I

That I claim as my invention, and desire to secure by Letters Patent, is

1. Preparing the metallic lead for the purposes of perfect corrosion byexposure to the action of acids or other substances in spangles of thesize and configuration substantially as herein described.

2. Preparing the metallic lead for the purposes of perfect corrosion byexposure to the action of acids or other substances by causing meltedlead to drop in a finely-divided stream or streams upon acorrugatedcylinder or its equivalent, revolving or moving so as to throw off solidspangles of more or less the form and thickness herein described.

In testimony whereof I have signed my name to this specification beforetwo subscribing Witnesses.

BENJ. F. SMITH.

Witnesses:

A. POLLAK,

WM. D. RUssELL

